不同屈光状态的模糊敏感度比较

Blur thresholds in different refractive groups

目的分析不同屈光组模糊阈值之间的差异,探讨模糊阈值在近视发生发展中的可能作用机制。方法38名志愿者参加本实验,正视组15位,等效球镜度为0.50～-0.50D;近视组23位,其中稳定性近视组17位,屈光不正平均为(-4.76±1.40)D,进展性近视组6位,屈光不正平均为(-3.33±1.43)D。受试者在屈光全矫基础上,采用JND标准测量模糊阈值。结果正视组模糊阈值为(0.21±0.06)D,稳定性近视组为(0.27±0.05)D,进展性近视组为(0.33±0.06)D。近视组的模糊阈值高于正视组(P=0.001),近视组中,进展性近视组的模糊阈值高于稳定性近视组(P=0.028)。结论近视对模糊的敏感度下降,其中进展性近视的敏感度下降更显著,这可能是近视调节滞后增加的部分原因。

Objective This study compared the ability of myopes and emmetropes to subjectively detect the presence of retinal defocus. Methods Subjects （15 emmetropes, 17 stable myopes, 6 progressive myopes） monocularly viewed a row of letters one or two lines above their best distance visual acuity through ＋1.00 D lenses placed over their best distance correction. Plus lenses were added in 0.12 D steps until subjects reported a just noticeable difference （JND） in blur. Results The mean blur thresholds for emmetropes, stable myopes and progressing myopes were （0.21±0.06）D, （0.27±0.05）D and （0.33±0.06）D, respectively. The blur threshold was significantly higher in myopes than emmetropes （P=0.001）. A higher blur threshold was also found in progressing myopes compared to stable myopes（P=0.028）. Conclusion These results demonstrate that myopes are less sensitive to the presence of blur, and this may in part explain the phenomenon that myopes show a greater accommodative lag. Additionally, the reduced blur threshold in myopes, especially in progressing myopes, may play a significant role in the development and progression of myopia.